Maternal thromboxane and prostacyclin levels in relation to fetal birth weight

Objective: To analyse whether pregnancies resulting in a small for gestatio nal age neonate are preceded by a prostacyclin deficiency or an imbalance b etween thromboxane and prostacyclin. Study design: At five fixed time point s during pregnancy, 24-h urine samples were collected fur the measurement o f thromboxane and prostacyclin metabolites thromboxane-B-2 (TXB2) and 6-ket o-prostaglandin F-1 alpha (6-keto-PGF(1 alpha)). In order to study trend di fferences between pregnancies with appropriate (AGA; n=26) and small For ge stational age neonates (SGA: n=17), trend analysis with simple contrasts we re accomplished for TXB2, 6-keto-PGF(1 alpha) and the TXB2/6-keto-PGF(1 alp ha) ratio. Results: Trend analysis showed higher TXB2 levels and higher TXB 2/6-keto-PGF(1 alpha) ratios in patients with SGA versus AGA newborns. No s tatistically significant difference in 6-keto-PGF(1 alpha) excretion betwee n patients with SGA and ACA newborns wasdetected. Conclusion: The birth of an SGA neonate is not preceded by prostacyclin deficiency. With ongoing pre gnancy an imbalance between thromboxane and prostacyclin becomes more obvio us in pregnancies with SGA newborns. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.